In an electric welding process, it is known to use a power cable for conducting current and sometimes shielding gas to a welding torch. The power cable is often referred to as a unicable, which generally includes a core tube, copper cabling and shielded lead wires. Typically, such a cable is connected to each end of a MIG torch by way of either a crimped style fitting or a threaded compression fitting. One end of the cable is fastened to a wire feeder by way of a mating pin, and the other end is fastened to a gooseneck or conductor tube of the welding torch. These connections are fixed and unmoving.
The conventional fixed connection limits the torsional movement of the copper bundles within the unicables and creates stress, leading to eventual failure of the electrical connection of the welding torch. Current designs of cables in the industry are installed in fixed positions, and during manipulation of the torch by a user or robot, the cable twists as the torch is turned. In newer robotic designs, this becomes problematic as the cable can be subjected to severe mechanical wear such that the fixed cable connections fail.
There are also several models of robots in the market that allow for a coaxial mounting of the welding torch. This means that the torch cable runs through the center axis of the robot. In the case of a coaxial mounted welding torch, any rotation of the robot axis that is coaxial with the cable puts rotational torque on the cable, thereby creating mechanical wear.